The present invention relates to the field of domestic bird production, and in particular, methods for feeding domestic birds to improve nutritional value, flavor, tenderness and/or consumer acceptability.
There have been numerous studies on feeding long chain omega-3 fatty acids to broiler chickens. The purpose of these studies was primarily to enrich the meat with omega-3 fatty acids in order to provide consumers with a non-fish based source of these fatty acids in their diets. In general, large quantities (xe2x89xa7approximately 6 g) of long chain omega-3 fatty acids were fed to the birds during the production period. As used herein, the terms production period and production cycle referred to the life cycle of the bird until slaughter. The researchers reported increased levels of long chain omega-3 fatty acids in the meat and flavor scores the same as or worse than control (non-enriched) broiler meat. The inventors are unaware of any studies reporting improved tenderness, taste or consumer acceptability of broiler meat when poultry are fed long chain omega-3 and/or omega-6 fatty acids.
In accordance with the present invention, a feeding method is provided for improving at least one of flavor, tenderness or overall consumer acceptability of fowl meat. As used herein, the term fowl meat means the meat of a bird, and in particular a domesticated bird that is fed a controlled diet. The method of the present invention includes the steps of providing a concentrated source of at least one of omega-3 highly unsaturated fatty acid (HUFA) or omega-6 HUFA, and feeding the concentrated source of at least one of omega-3 HUFA or omega-6 HUFA to fowl in low concentrations resulting in improvements in at least one of flavor, tenderness or overall consumer acceptability of the meat of the fowl. An additional advantage of the present invention is that the nutritional value of the fowl meat can also be improved, for example, by increasing the level of omega-3 HUFA and/or omega-6 HUFA in the meat.
As used herein, the terms highly unsaturated fatty acid or HUFA mean a fatty acid with four or more unsaturated bonds. Examples of HUFAs include arachidonic acid (ARA(n-3), C20:4n-3 or ARA(n-6), C20:4n-6); stearidonic acid (SDA, C18:4n-3); eicosapentaenoic acid (EPA, C20:5n-3); docosahexaenoic acid (DHA, C22:6n-3) and docosapentaenoic acid (DPA(n-3), C22:5n-3 or DPA(n-6), C22:5n-6).
Preferably, a concentrated source of both omega-3 HUFA and omega-6 HUFA is provided and is fed to the fowl. Preferably, the ratio of omega-3 HUFA to omega-6 HUFA is in the range from about 2:1 to about 4:1. Preferably, the omega-3 HUFA is selected from the group consisting of DHA, EPA, DPA(n-3), ARA(n-3), SDA and mixtures thereof. Preferably the omega-6 HUFA is selected from the group consisting of ARA(n-6), DPA(n-6) and mixtures thereof. More preferably, DHA and DPA(n-6) are provided and are fed to the fowl. More preferably, DPA(n-3) and DPA(n-6) are provided and are fed to the fowl.
Preferably, the concentrated source of at least one of omega-3 HUFA or omega-6 HUFA is provided and fed to said fowl predominantly in the final 50 percent of the fowl production (life) cycle and more preferably, the concentrated source of at least one of omega-3 HUFA or omega-6 HUFA is provided and fed to said fowl predominantly in the final 25 percent of the fowl production (life) cycle. As used herein, the term predominantly means at least 50 percent, more preferably at least 66 percent and more preferably at least 75 percent. A feeding protocol is disclosed in U.S. Pat. No. 6,054,147 entitled xe2x80x9cA Method For Increasing The Incorporation Efficiency Of Omega-3 Highly Unsaturated Fatty Acid In Poultry Meatxe2x80x9d, which is incorporated herein in its entirety by reference.
Preferably, the concentrated source of at least one of omega-3 HUFA or omega-6 HUFA is provided and fed to the fowl during its production cycle in an amount comprising from about 0.2 to about 2.4 grams of HUFA per kg of the final body weight of the fowl, more preferably in an amount comprising from about 0.4 to about 1.75 grams of HUFA per kg of the final body weight of the fowl, more preferably in an amount comprising from about 0.6 to about 1.25 grams of HUFA per kg of the final body weight of the fowl, and more preferably in an amount comprising from about 0.7 to about 1 grams of HUFA per kg of the final body weight of the fowl.
Preferably, at least 25 percent of the total fatty acids in the HUFA source added to the fowl ration and consumed by the fowl are omega-3 HUFA, omega-6 HUFA or mixtures thereof, more preferably at least 30 percent of the total fatty acids in the HUFA source added to the fowl ration and consumed by the fowl are omega-3 HUFA, omega-6 HUFA or mixtures thereof, more preferably at least 40 percent of the total fatty acids in the HUFA source added to the fowl ration and consumed by the fowl are omega-3 HUFA, omega-6 HUFA or mixtures thereof, and more preferably at least 50 percent of the total fatty acids in the HUFA source added to the fowl ration and consumed by the fowl are omega-3 HUFA, omega-6 HUFA or mixtures thereof.
Preferably, the domesticated bird or fowl is selected from the group consisting of broiler chickens, roaster chickens, turkeys, guinea hens, quail, ducks and geese, more preferably the domesticated bird or fowl is selected from the group consisting of broiler chickens, roaster chickens and turkeys.
Preferably, the omega-3 or omega-6 HUFA are provided in the fowl feed in the form of triglycerides, phospholipids, ethyl esters of the fatty acids or mixtures thereof.
Preferably, the omega-3 or omega-6 HUFA is from a microbial source, animal source (including fish oil or meal) or a genetically engineered plant source, and more preferably the omega-3 or omega-6 HUFA is from Schizochytrium sp or Crypthecodinium sp.
Preferably, the method of the present invention results in the enrichment of the meat in at least one HUFA, more preferably in the enrichment of the meat in at least one of DHA, SDA, EPA, DPA(n-3), DPA(n-6), ARA(n-3) or ARA(n-6), more preferably in the enrichment of the meat in at least one omega-3 fatty acid and more preferably in the enrichment of the meat in DHA.
While conducting tests on enriching poultry meat with omega-3 fatty acids, the option of feeding much lower omega-3 and omega-6 long chain HUFA contents in their rations than had previously been tested was investigated. When a test panel evaluated cooked meat samples, it was unexpectedly found that the enriched meat had higher taste, tenderness, and overall acceptability scores than the control meat. Thus it was found that the meat could be significantly enriched with omega-3 fatty acids (with about 2 to 6 times the amount of long chain omega-3 fatty acids found in regular meat) by providing nutritionally significant levels of long chain omega-3 fatty acids. This is an additional benefit to consumers because of the well-known health benefits of long chain omega-3 fatty acids. At the same time however, the overall consumer acceptability of the meat as compared to regular meat could also be improved. Another benefit is that the overall polyunsaturated fat content of the meat is increased also improving the nutritional quality of the meat for consumers.
While not wishing to be bound by any theory, the benefit of low levels of long chain omega-3 and omega-6 HUFAs in poultry rations is most likely due to DHA and in this case DPA(n-6) substituting for shorter chain and less unsaturated fatty acids in the phospholipids of the meat. This substitution could improve the fluidity of the phospholipids membranes and directly impact the other functional properties of the meat. This effect of low levels of enrichment has not been observed previously possibly because of the emphasis on high levels of enrichment, higher levels of incorporation may lead to too much fluidity in the membranes adversely affecting functionality and/or cause enrichment of significant amounts of triglycerides in the meat which are less stable leading to organoleptic problems. Additionally many previous studies used less concentrated forms of omega-3 fatty acids such as fish oil that has about 20-25% omega-3 fatty acids as % total fatty acids. The other 75% of the oil is made up of saturated and monounsaturated and some polyunsaturated fatty acids that can also incorporate in the meat in an untargeted manner causing unwanted functionality problems. By using a more concentrated form of highly unsaturated fatty acids in the omega-3 and omega-6 series, in one embodiment about 55% of the fatty acids in the LCHUFA source were DHA(n-3) and DPA(n-6) fatty acids, the enrichment of the phospholipids can be directed more accurately to substitution by these highly unsaturated fatty acids. Additionally it is possible that use of the longest chain fatty acids in the omega-3 and omega-6 series provides fatty acids with the most potential for influencing the fluidity of the phospholipid-based membranes in the meat because of the high level of unsaturation in these fatty acids and because of the positive impact of the tertiary structure of these fatty acids (e.g. helical structure of DHA making it able to tightly pack in membranes like a saturated fatty acid but have the flexibility of a highly unsaturated fatty acid.
In the omega-3 series DHA, EPA, DPA, ARA and SDA can be used but more preferred are DHA and DPA(n-3). In the omega-6 series sources of ARA and DPA(n-6) can be used but DPA(n-6) is more preferred.
The HUFA supplement preferably contains long chain omega-3 fatty acids, more preferably DHA, more preferably DHA and a long chain omega-6 source, most preferably DHA(n-3) and DPA(n-6). Preferably, low levels of omega-3, preferably DHA, are fed to the fowl. Preferably, some long chain omega-6, preferably DPA(n-6), is fed to the fowl. Preferably, the ratio of omega-3 HUFA to omega-6 HUFA is in the range from about 2:1 to about 4:1. Preferably, the long chain omega-3 and omega-6 fatty acids are fed to the fowl during the last half of the production cycle and more preferably during the last 25% of the production cycle.
The amount of long chain omega-3 and omega-6 HUFAs fed during the production cycle are preferably in the range from about 0.2 to about 2.4 g/kg final body weight, more preferably from about 0.4 to about 1.75, more preferably from about 0.6 to about 1.25, and more preferably from about 0.7 to about 1.0 g/kg final body weight. Preferably, a concentrated form of long chain omega-3 and/or omega-6 polyunsaturated fatty acids is fed to the fowl.
Preferably, greater than 25% of the total fatty acids are omega-3 and/or omega-6 long chain HUFA, more preferably more than 30%, even more preferably 40%, and most preferably greater than 50%.